Art of recording and reproducing sounds



Jan'. i9 1926.

' F. L. DYER RT OF RECODING' AND RERODUGING SOUNDS l Filed lvay v, 1923 4 sheets-'sheet 2 IN VEN TOR Jan. 19 1926. 1,5'7o,z97

F. L. DYER ART OF RECORDING AND REPRDUCING' SOUNDS Filed May 7,' 1925 44, sheets-sheet s lll/1111111111@ INVENTOR Jan. 19 1926. 1,570,297

A F. L. DYER ART OF RECORDING AND REPRODCING SOUNDS Filed May 7, 1923 4 Sheets-Sheet 4 UW' i we 31 ik Inl" f' INVENTR Patented Jan. 19, 192e.

UNITED `s i ART OF RECORDING AND REIYRODUCING SOUNDS.

Application led May v7,

To all whom, t may concern.'

Be it known that I, FRANK L. DYER, a cit-izen of the United States, residing at Montclair, in the county of Essex and State of New Jersey, and having a post-office address at No. 115 Broadway, New York city, have invented certain new and useful Improvements in the Art of Recording and Rteproducing Sounds, of which the following 1s a full, clear, and exact specification.

My invention relates to improvements 1n the art of recording and reproducing sounds. As now made, talking machine records permit the recording of sounds over a very limited period of time, generally in the neighborhood of three minutes, more orv less; as a result any music recorded thereon 1s necessarily abridged and mutilated, and socalled talking records are limited in subject matter.

The limitation as totime in existing talking machine records is made necessary by the conditions of the art as now practiced. being an essential that the sounds which are to be direct-ly reproducedfrom the record shall be loud enough to lill a large sized room, it has been found necessary to make use of a relativelyi ponderous sound-box carrying arelatively vlarge diaphragm, the whole resting upon a pointed needle which tracks the record and which engages the record with a pressure pounds per square inch. To prevent such a needle from cutting and destroyingthe record material with which it engages, 1t 1s necessary that the record material should be moved with respect to the needle at a relativelyv high speed. andexperience has shown that a mean surface speed in the neighborhood of 40 inches per second is desirable 1 n practice. It has been found that at this surface speed of the material a sound-box of sufficient weight to give the necessary sounds can be supported by a needle with commercial results as to wear, provided the record groove is of sufficient width to givea relatively extended bearing surfacefor the,

needle when the point of the latter has worn down sutliciently to fill a substantial portion of the record groove, and therefore it is the present practice to make these v record lgrooves substantially .005 inch in width and with a depth ranging from .002 to .003 inch.

The amplitude ofthe sounds reproduced from the record depends upon the extent to which the groove may vary on either side of many thousand 1923. Serial N0. 637,198.

ofits medial line or in other words upon the. amphtude of the lateral or vertical undulations of the record groove, and I have observed from a study of many records that the maximum sounds recorded represent a vibration -of between .001 and .002 of an inch. To permit the recording of sounds representedby an amplitude of this order.

or possibly greater, and at the same time provide sufficient Imaterial between adjacent groovesto properly actuate the needle and prevent it from short-circuiting, it has been necessary in practice to employ a .feed of t-he order of .O1 inch, whereby the lands between the grooves will be of a mean width of .005 inch corresponding'with that of the rec-ord groove. These limitations as to width of groove, width of lands, and surface speed make it impossible with a record disk of a diameter of 10 or 12 inches or thereabouts, or -a corresponding cylinder, to secure a sound record of much more than 3 minutes in` length, with corresponding restriction as to character and subject matter.

What I propose by my present improve- TATES PATENT oFF-ICE.

ments, is to very greatly extend the capacity of a record of the present standard size by obtaining thereon a record of sounds of an hour or morerepresenting an extension of 25 fold'as to time. In this way it will become possible to record ve'ry compositions or to record several long musi-- cal compositions on one face of a record; it will become possible to make a record of stories of considerable-length: it will become possible on two or three double faced records to record an entire novel, since three records would represent six hours of solid reading; and it will become possible to record upon a record disk of very small size a much longer selection than can possibly be recorded and satisfactorily reproduced underexisting conditions on records of standard size. My'improved record will be especially acceptable tothe blind, to whom reading by existing methods is tedious and unsatisfactory.

What AI-propose, in brief, is to make a -record groove of microscopic size, preferably of the order of .O01 .inchl in width, or at least substantially and materially narrower than any talking machine record which I have knowledge. The depth of the groove is not important, so long as it shall be in reasonable proportion to the width. I have frequently cut record grooves of the order of a thousandth of an inch in width long musical ofY material is sufficiently uniform and amorphous to permit such a groove to be cut with great smoothness and sharpness.

In cutting a record groove of the Width indicated, I make use of a proportionate surface speed or approximately so; that is tosay, if the width of the groove is reduced five-fold to .001 inch, the surface speed is preferably reduced in prop-ortionto preferably. a shaft speed of about 16 turns per` minute or a mean surface speed of the order of eight inches per second.

The sounds which I record in such a groove of extreme narrowness and formed at low speed are so controlled or adjusted that the recorded amplitude thereof will bear substantially the same ratio to the surface speed as with existing practice; that is to say, if the maximum amplitude of sounds as recorded'on present records is of the order of .001 inch, then with my improved record the recorded amplitude will be approximately .0002 inch. This control of the sounds Vto be recorded may be effected in many wa s, as by using original sounds of small vo urne, or by' using a recording diaphragm of relatively great thickness to limit the am litudey of its response, or by using a recor ing diaphragm of small diameter so as to have a limited response, or by adjusting the leverage o-f the needle arm of the recording device whereby the movement of the cutting stylus will be properly limited.

It will be seen that the proposed record will have substantially the same relations as to Width, surface speed and amplitude as existing records. With such a record it becomes possible to make a proportionate reduction in the pitch of the record groove; with the example under consideration the pitch will be reduced from .01 inch to .002`

inch.

By cuttingdown the pitch of groove fivefold and by reducing the surface speed five-l fold, I increase the time represented by the record groove twenty-five fold or, say, from three minutes to seventy-five minutes, while at the same time the record groove has sounds recorded thereon in proper relation to the surface speed as Well as to the width of-groove and width of lands between the rooves. The sounds recorded in the groove iifer only from the sounds in the grooves of existing records in theJ respect that they are of less amplitude, but otherwise they are perfectly and accurately formed. Be-

.ing recorded at low speed and involving the removal of a minute amount of' material the recorded sounds are relatively free of distortionsnoticed in existing .records which are due yto removal of relatively large amounts of material at relatively high speeds. A

Such a record as I have above proposed,

could not be used eectively for direct reproduction; a sound box for thatk purpose would have to be too heavy and direct reproduction under any circumstance Would be Weak, owing to the limited amplitude of the recorded sounds. I, therefore, propose to use a reproducing device bearing upon the record with a. pressure proportional to the width and length of the groove, say with a pressure of from one-quartei to one-half an ounce, and by suitable amplifying means I increase the volume o-f the soundsvto the desired extent. It is possible to use exterior amplifying means to enlarge the comparatively feeble sounds on the record to any desired extent; to as loud or louder than existing records with direct reproduction, while at the same time the wear on the improved record is no greater than with present records. The sounds from my improved record may be amplified in any suitable Way, for instance, for reading, ordinary listening tubes or a' simple telephone may be employed, while if loud effects are wanted, the feeble sounds on the record may be amplified by an ordinary loud-speaker of the radio type o-r some such device having as many stages of amplification as may be desired. Devices of 'this kind are capable of producing enormous amplification with but relatively little distortion. If listening tubes or a stethoscope is used `as an amplifying device, it will be understood that the reproducing device will be equipped with a small light diaphragm actuated directlyr from the record, but if the amplifying de-` vice is electrical, as is preferred, then the needle tracking the record groove will actuate a suitable microphonethe varying currents of which Will either actuate a telephone receiver directly or be amplified before reception by any suitable arrangement of thermionic valves or other amplifiers.y

In order that the invention may be better understood, attention is directed to the accompanying drawings forming part of this specification, and in which:

Fig. 1 is a cross sectional view of a record of the ordinary type and dimensions, illustrating three of the grooves, with the lower end of a needle engaging the center groove;

Fig. 2, a corresponding cross section through my improved record, on the same scale, with a-needle engaging one of the grooves;

Fig. 3, a plan View of the standard record shown in Fig. 1;

Fig. 4, a similar view of the improved record;

Fig. 5, a plan view of a portion of an apparatus for reproducing from my improved record, employinga microphone as a transmitting device;

Fig. 6, a side elevation of Fig. 5, partly looking in the represent `a nine-fold is formed is approximately second, average;

Ain section, looking in the direction of the arrow 6;

Fig. 7 a section on the line 7 -7 of lFig. 6; Fig. 8, a cross sectional view, on a larger scale, -sho'wing y'the details of a suitable microphone arrangement; v g y.

Fig. 9, a section at right angles to Fig. 8,

direction of the arrow 9;

Fig. 10, an elevation partly broken away showing a suitable arrangement of carrying case for the apparatus for reproducing from my improved record; and

Fio'. 11, a suitable circuit, in diagram,

showing one stage of amplification for use with reproducing apparatus herein referred In all of the above views corresponding parts are represented by the same reference characters. Y

-Referring first to Figs. 1 and 3, 1 represents a small portion of an ordinary record having a record groove 2 therein; ordinarily this record groove is about .005 inch in width, about .002 in depth, and with a pitch of .01 inch or one hundred threads tothe inch. In Fig. 3, the groove is shown as having adeflection, representing sound, of .001 inch, this beingpthe order of amplitude of Amaximum sounds recorded on talking machine records. It will belunderstood that the record is a duplicate copy obtained in the usual way from a suitable master cut in an amorphous and uniform mater-al in the usual way.

Referring now to, Figs. 2 andl 4, the record groove 3, s hown therein is illustrated as being one-fth the width of the ordinary groove and one-fifth the relative length thereof; that is to vsay the groove is .001 inch in width and the surface speed at which it eight inches per its depth is substantially proportional to the standard record shown in Figs. 1 and 3. With these proportions the record, asvshown in Fig. 4 has one twenty-tifth the area of the standard record and hence the time of reproduction is increased twenty-five fold. It is of course not necessary that vthese dimensions shall be precisely followed; by reducing the width of the groove and proportionately reducing the surface speed the timeof reproduction is increased in proportion to the product of the two factors; a record of one-third the usual width -and one-third the speed will increase in time. and so on. It is important that'there should lbe a substantial reduction in the width' and surface speed as compared with present practice, since" the opportunity of exterior amplification -is practically unlimited and the important consideration is to increase the time of reproduction at. least several fold so as to thereby extend the talking machine-.into fields that are now unthoughtfof.

It will be observed that the amplitude Aof the recorded'sound in Fig. 4 is proportional to that of Fig. 2, so far as width and length are concerned. In other words, the maximum amplitude with a record groove of .001 inch should be of the order of .0002 inch. As I have indicated a sound groove of this sort can be obtained in various ways, but of the expedients suggested I prefer to secure the desired limited range of amplitude by using an ordinary recording apparatus operated in the usual way, but I so adjust the leverage of the arm or lever which carries the cutting tool that the deviation of the cutting tool will be properly reduced in extent; in the assumed case, the leverage will be such that the cutting tool will be vibrated only one-fifth as far on either side of the medial line as with present practice.

As indicated, the feed or pitch of the record groove is reduced in proportion tothe width, .that is-to say when the width of the groove is reduced yto .001 inch, the pitch of the groove will bereduced to .002 inch or five hundred threads to the inch.

The needle 4, which tracks the groove ofy my improved record is properly Vproporf Qordinary needle 5 tracking the regular sized groove 2; in use the relatively pointed end will quickly wear down to increase the bearing surface and fill the groove more or less; it is important that theI extremity of the needle shall have the right proportion; the shank may bey relatively large so as to give rigidity and permit the needle to be handled more easily. I find that the ordinary recording material is so uniform and amorphous that a sound groove of .001 inch in width may be cut therein with beautiful sharpness and clearn'ess; moreover the methods now used of making duplicate copies from master records are so veryfperfect that even when thev record has been reduced in width five fold as contemplated .herein the copies obtained from such a master will be practically perfect and free from foreign sounds. i.

VIn 'securing reproduction from such a record as I have above described, I take advantage of exterior amplifying devices and I prefer to have the record actuate a microphone rather than a diaphragm as when the amplification is secured by the use of a stethoscope. trical amplification although it will be understood that the reproducer needle may actuate a small and sensitive diaphragm the feeble vibrations of which may be detected bythe use of listening tubes.

My improved record, Ishown in Fig. 6, at 6, is carriedA on a turn-table' 7 driven in any suitable way, as by Aan electric-motor, illustrated conventionally at 8, in Fig. 10.

I will therefore describe elecy It is turned at a speed equal to that at which the master was made; in the assumed case of a record groove of .O01 inch in a 10 or 12 inch disk the shaft speed Will be preferably about sixteen turns per minute.

The needle 4 is carried in a suitable holdp er 9 atrthe end of a lever 10, mounted to vibrate on pivots ll, 11, with as' little friction as possible and with no lost motion. The pivots are mounted in a suitable casing 12, Within which is the-lever 10, and said casing is provided With integral eX- tensions 13, 13, giving room for a tension wire 14, to which the upper end of the lever is connected. Said tension Wire offers an elastic 'support for the upper end of the lever or needle-arm and permits the latter to vibrate like a reed; at the same time the wire is practically aperiodic or at least its funda-- mental is so high as to be Without effect.

The microphone-reproducer described is carried at the extremity of an arm or tube 19, which may be an integral extension of the casing 12. This arm is mounted on horizontal pivots 20, 20, in a. ring 21, and the latter is mounted'on a vertical pivot 22, as shown particularly in Fig. 7, whereby the arm 19 may be free to swing laterally as the needle tracks the groove and also it may be lifted off of the record when desired. It Will be seen that the construction described is very light as it is important that the pressure of the needle on the record shall be only a fraction 'of an ounce. In order that the parts may not be fragile and at the same time to secure` the desired lightness of pressure, I preferably employ an adjustable counteracting spring 23, arranged between the arm 19 and an arm 24, projecting from the ring 21, whereby the counteracting spring will be unchanged in its relation' to the arm 19. v

Preferably thering 21. is provided with a pointer or indicator' which cooperateswith a suitable scale 26, to facilitate engaging the needle with the record at any desired point thereon. n Y The microphone may be connected in any desired circuit for the purpose; it may be' arranged in a simple circuit with a. battery and a telephone receiver or head-set. `Or

'it may be connected in circuit with a loud-- speaking device, such asare used for radio reception, with as many amplifiers as may be desired; for instance, in Fig. 11, I show the microphone contacts in acircuit 27, which is coupled to an amplifying circuit 28, the` table and reproducing mechanism, and also provided with a hinged front 31, which may be let down to disclose the motor 8 and batteries 32 for 'the telephone current. It is intended, if an electric motor is used that it will be operated from a suitable storage battery or from the usual light circuit.

lVhile I have specifically described my improved talking machine record as having a groove of the laterally undulatory type, it will be understood that the invention may becarried out with records having hill and dale grooves, it being only necessary to properly proportion the Width, length and amplitude as herein described. If the hill and dale groove is adopted, I prefer to form the same With a Wedge shape cutter, giving substantially the cross-section of Fig. 3. lVith such a groove, a needle may be used for reproduction, and Will track the groove with facility and certainty. A groove of this kind is preferred to one formed With a curved edge cutter and in Which the groove is extremely shallow and relatively Wide, since with such a groove a rounded reproducing stylus is used, generally a sapphire or diamond, and difficulty would be experienced inl tracking the groove if reduced to the microscopic dimensions contemplated by my invention.

Having now described my invention, what I claim as new therein and desire to secure by Letters Patent, is:

1. In the art of reproducing sounds, a talking machine record having a sound groove materially less than .005 inchin Width, representing sounds recorded at a surface speed .materially less than forty.

inches per second, a reproducing device having' a needle engagingthe record with a pres- 'representing sounds recorded at a surfare speed of approximately eight inches per second, a reproducing device having a needle engaging the record with a ressure of less than'one ounce and means or securing an amplified response Vfrom said needle sub. stantially as set forth.

tude-of approximately .0002 inch recorded at a surface speed of approximately eight inches per second, a reproducing device having a needle engaging the record with a pressure less than one ounce and means for securing an amplified response vfroni said needle substantially as set forth.

4. In the* art of reproducing sounds, a.

talking machine record havin a microscopic groove in width, length an amplitude as compared with existing practice, the values of Width and length being so chosen as to permit the recording on a ten inch disc of sounds extending over a period of ten minutes or more, a needle engaging the record groove With'a pressure sufficiently light as not to result in substantially greater Wear than with existing r'actice, and means for securing an ampli ed responsefroml said needle, substantiall as set forth.

5. In the art o reproducing sounds, a talking machine record having a microscopic groove in width, length and amplitude as compared with existing practice, the values of Width and len th being so chosen as to permit the recording on a ten inch disc of sounds extending over a period. of ten minutes or more, a needle engaging. the record groove with a pressure suiiiciently light as not to result in substantially greater wear than with existing practice, a telephone transmitter actuated bythe needle, and a magnetic receiver actuated b the telephone current, substantially as set orth.,

6. In the art of reproducing sounds,atalk ing machine record having a microscopic groove in width, length and amplitude as compared with existing practice, the values of width and length being so chosen as to permit the recording on a ten inch disc of sounds extending over a period of ten min'- utes or more, a needle engaging the record groove with a pressure sufficiently light as not to result in substantially greater wear than with existing practice,l a telephone transmitter actuated by the needle, .a thermionic amplifier for amplifying the telephone current, and a magnetic receiver actuated by the amplified' current, substantially as set forth.

7. In the art of reproducing sounds, a talking machine record having a groove approximately .001 in width `and representing sounds recorded at a surface speed of aproximately eight inches per second, a neele engaging the record groove with a very light pressure, a telephone -transmitter actuated by the needle, a thermionic amplifier for amplifying the telephone currents and a magnetic receiver actuated by the amplified currents substantially as set forth.

8.` In the art of reproducing sounds, a sound record groove of microscopic width representing sounds of feeble amplitude recorded at a low surface s eed, the values of width and surface speed eing so chosen as to permit sounds extending over a period of ten minutes or' more to be recorded on a ten inch disc, a telephone transmitter actuated `by the record groove, a thermionic amv plifier for amplifying the feeble telephone currents, and a radio loud speaker actuated by the amplified currents, substantially asI set forth.

9. In the art of reproducing sounds, a sound record groove substantially less than .005 in Width representing sounds recorded at a surface speed substantially less than forty inches per second and of such feeble amplitude as to be incapable of direct mechanical reproduction through a horn, a

telephone transmitter actuated by the record groove, a thermionic amplifier for amplifying the feeble telephone currents, and a radio loud speaker actuated by the amplified currents, substantially as set forth.

10. In the art of reproducing sounds, a sound record groove substantially less than .005 in width representingv sounds recorded at a surface vspeed substantially less than forty inches per second and of such feeble amplitude as to be incapable of direct mechanical reproductionthrough ahorn, and means for securing an am lified res onse fromsaid record, substantie ly as set orth.

11. In the art ofreproducing sounds, a

talking `machine record having a sound groove therein, a needle engaging the record` groove with' a pressure of less than ci'iejv ounce, means! for converting the vibrations-,p

ofthe needle into feeble telepione currents, i

thermionic means for ampli ing said currents, a magnetic receiver actuated by thtmplified currents, substantially as set 12 I n the art of reproducing sounds, a talking machine record havin a sound groove therein representing soun s too faint ory direct mechanical reproduction through 4a horn, a needle engaging the record'gi'oove with a pressure of less than one ounce, means for converting the vibrations of theneedle into feeble tele hone currents, thermionic means for amplifyingsaid currents, and a magnetic receiver actuated by the amplified currents, substantially as set forth.

This specification signed this fifth day of May', 1923.

FRANK L. DYER. 

